4. Arduino Uno Prototype
This prototype was created to verify the components and code. It was also used to field test the completed design. The size of the enclosure ony allowed for electrons the 110 volt power outlet was put into a separate component.
The user interface is the LCD Display and the KY-040 Rotary Encoder. The encoder is used to switch between displays. If pressed the system enters a setup mode where various properties may be set.The following properties are currently implemented.
- Target Temperature
- Temperature Units Fahrenheit or Celsius
- Deviation range from target
- Control Auto / Heat / Cool
The following is the general component placement for this configuration. Right angle headers are used for connecting components using Female/Female Jumper Wires. This allows for easy re-configuration when necessary.
A prototype board was selected which includes power and ground pins. As the enclosure did not have height Double Row Right Angle PCB Pin Headers were used to provide easy wiring for power and ground using Female/Female Jumper Wires. Two of the pin pairs do not have headers to allow for direct wiring.
SDA Pin connected to A4, SCL is connected to A5. Power and ground pins are also connected.
There is a 10K 1/4W 5% Resistor for KY-040 SW Pin for hardware de-bouncing connected inline between power and pin 12. Pin 10 is connected to CLK on KY-040, pin 3 is connected to DT on KY-040. Power and ground are also connected to the KY-040.
On the Sparkfun BlueSmirf Bluetooth interface the TX is connected to pin 4, RX is connected to pin 5. Power and ground are also connected.
IN1 on the relay switch is connected to Arduino PIN 6 for heat. IN2 on the relay switch is connected to Arduino PIN 7 for cool. Power and ground are also connected.
WARNING: When connecting to mains voltage, you really need to know what you are doing, otherwise you may shock yourself. This is a serious topic, and we want you to be safe. If you’re not 100% sure what you are doing, do yourself a favor and don’t touch anything. Ask someone who knows!
There is a 4.7k 1/2 Watt 5% Resistor inline from Power to the yellow Temperature data wire connected to pin 9. Power and ground wires are also connected.
